Street sweeper brush and assembly



April 1, 1941. R. c. EVANS STREET SWEEPER BRUSH AND ASSEMBLY Filed May 12, 193B 5 Sheets-Sheet 1 MH. .En mh au, lnxwwmaf su mw Qa/VAL o @SM2-Afr fnv/YS.

April l, 1941 R. c. EVANS 2,236,816

STREET SWEEPER BRUSH AND ASSEMBLY Filed May l2, 19258 5 Sheets-Sheet 2 HIIIII- -I Marlin-lll April 1 1941l l R. c. EVANS 2,236,816

STREET SWEEPER BUSH AND ASSEMBLY Filed may 12, 195B 5 sheets-sheet s R. C. EVANS STREET SWEEPER BRUSH AND ASSEMBLY Filed May 12, 1938 April l, 1941. v

lApril l, 1941 R. c. EVANS 2,236,816

STREET swFEPERV BRUSH AND ASSEMBLY Filed May 12, 1958 5 sheets-sheet s Patented Apr. 1, 1941 STREET SWEEPER BRUSH AND ASSEMBLY Ronald Clement Evans, Elgin, Ill., assignor to Elgin Sweeper Company, Elgin, Ill., a corporation of Illinois Application May 12, 1938, Serial No. 207,446

10 Claims.

This invention relates to street sweeping apparatus, and more particularly to a novel caterpillar sweeper brush and brush assembly.

The subject matter hereof is related to that of my copending applications Serial Nos. 297,443, 207,445, and 216,740, the rst two of which were led on May 12, 1938, and the latter of which was iiled on June 30, 1938.

Many forms of street sweepingV apparatus have been employed in the past for sweeping streets and other surfaces to be swept. The dilerent forms of sweeping apparatus may be roughly classified as caterpillar brush sweepers, rotary brush sweepers, and combined rotary brush con-- veyor sweepers. Caterpillar brush sweepers have not met with the same degree of success as the other two types of sweepers. There may be many explanations for this, but the principal one appears to lie in the fact that an eiicient caterpillar brush and brush assembly has not as yet lbeen designed which could be manufactured at a reasonable cost and be rugged and reliable in use.

It is an object of the present invention to provide a novel sweeper brush and brush assembly which is economical to manufacture, which is rugged and reliable in use, and which is eX- tremely ecient in operation.

Another object of this invention is to provide a novel form of 'caterpillar brush and caterpillar rush assembly.

A further object of this invention is to provide a novel means for securing brush bristles and iibres to a pair of endless articulated chains.

Another and further object of this invention is to provide a novel caterpillar sweeper brush assembly made up of a plurality of individual brush units which may be quickly and easily removed and mounted in the assembly.

Another and still further object of this invention is to provide a novel means for adjusting the relative position of the caterpillar brush and for tensioning the brush and brush assembly.

A still further object of this invention is to provide a novel caterpillar brush floating mount.

Still another object of this invention is to provide a novel multi-part housing including provisionfor obtaining ready access to the caterpillar brush.

Still another object of this invention is to provide a novel type of dirt shoe.

'Ihe novel features which I believe to be characteristic of my invention are set forth and described with particularity in' the appended claims. My inventionV itself, however, both as to its construction and organization, together with further objects and advantages thereof, may best be understood by reference to the following description taken together in connection with the accompanying drawings, in which:

Figure 1 is a side elevational View of a street sweeping apparatus employing a caterpillar brushk embodying the principles of the present invention;

Figure 2 is an enlarged fragmentary elevaltional view illustrating the lower end of the caterpillar brush assembly;

Figure 3 is a cross-sectional View of the caterpillar brush assembly of Figure l;

Figure 4 is an isometric, exploded view of the brush head;

Figure 5 is an enlarged cross-sectional end view of a brush unit;

Figure 6 is an enlarged fragmentary front View, partly in cross-section taken verticallyv View of the dirt shoe and dirt shoe mounting taken along the line IX-IX of Figure 1;

Figure 10 is a cross-sectional View of a modied form of brush head;

Figure 11 is a, fragmentary elevational view of the brush assembly, showing a modified form of endless chain tensioning device; and

Figure 12 is a skeleton view taken along the line XII-XII of Figure 11, showing the modied form of tensioning mechanism illustrated therein, but with the other elements of the apparatus eliminated from this view for the purpose of clarity.

The sweeping apparatus illustrated in Figure 1 of the drawings is a street sweeper of the caterpillar brush type. The sweeping elements of this apparatus, together, with their associated elements are mounted on a motor driven vehicle I0, the principal component parts of the complete apparatus being the caterpillar brush assembly I I, a dirt and debris storage hopper I2, and a chassis I3, having a rear-mounted motor` I4 thereon (the motor being diagrammatically indicated by showing the customary hood enclosing the same). The chassis I3 includes a pair of front wheels I5 mounted on a xed axle (not shown) and a pair of rear wheels I6 which upper forward wall of the body I9, a relativelyv large transverse opening is provided to permit access to the upper portion of the caterpillar brush assembly Ii. This transverse opening in the upper forward wall of body I9 is closed by a sliding cover 29 which is held in desired position by a pair of iiange members 2| welded or otherwise suitably secured to the top of body I9, the flanges 2| being so arranged as to permit transverse sliding movement of the cover 20.

The dirt and `debris collecting hopper I2 is situated at the extreme forward end of the vehicle I and communicates directly with the upper portion of the brush assembly II. designed to receive dirt and debris carried upwardly thereto by the sweeping apparatus and to store the same until it is desired to empty hopper I2. Lower end wall 22 of the dirt and debris collecting hopper I2 is pivotally mounted to the end of chassis i3 by `a pair of hook shaped arms 23 which are pivotally secured to the horizontal fiame members of the chassis I3 as at 24.

In lorder to hold the end wall 22 of hopper I 2 in its closed position so as to prevent escape of dirt i' and debris from the hopper, a flexible cable or chain 25 is employed to hold end wall 22 in place. Chain 25 is connected at one end to end wall 22, is then passed `over a sheave 26 secured to the side wall of the body I9, and is connected finally at its opposite end to a dump lever 21. The dump lever 21 is pivotally mounted on the body I9 as at 28, its downward angular movement being limited by a suitable stop means (not shown) to the position shown in Figure 1. tion the lever is in an over-center position which automatically locks the end wall 22 in its closed position. When dump lever 21 is moved upwardly and forwardly, the forward movement of the exible cable or chain 25 permits the end wall 22 s to open by virtue of its own weight.

The caterpillar brush assembly II includes in general a caterpillar brush 29, and a caterpillar brush housing 30, composed of an upper stationary housing portion 3l and a lower movable housing portion 32 arranged for limited angular movement about a transverse axis. More speciically, lower housing portion 32 is hinged to and supported by upper housing portion 3I as at 33. The rear wall 34 of the housing portion 32 is preferably given a segmental cylindrical curvature, and the lower end 35 of the top wall of the upper housing portion 3| is similarly curved but arranged to permit the lower housing member 32 to be telescoped thereover. The side walls of lower housing member 32 overlap the side walls of upper housing member 3l even when the former are in their lowermost position. This substantially complete telescopic engagement of the lower housing member 32 with the upper housing member 3l permits the former to be raised and lowered without any substantial interference from the latter.

In order to permit ready accessibility to the caterpillar brush 29 to repair or replace a por- Hopper I2 is In this position thereof, in a manner which will presently be explained, the rear wall 34 includes a pivotally mounted panel 36 which preferably extends over a major portion of the rear wall 34.

The caterpillar brush assembly II also includes a pair of dirt shoes 31 carried on the lower housing portion 32 by arms 38, the latter being pivotally connected to the shoes 31 as well as to the housing portion 32. Dirt shoes 31 are in the form of runners which ride along the street surface, the forward and rear ends 39 and 40 being turned up for that purpose. These shoes prevent dirt and other debris from being thrown out of the side of the sweeping apparatus. A stop block 4I on each side of the housing portion 32 engages the arms 33 when the housing portion 32 is raised, and this carries the shoes 31 up with it. The specific structural characteristics of the dirt shoes 31 will presently be described in detail.

In order to provide continuous and efficient sweeping irrespective of ripples and the like in the street surface, a floating mount 42 is provided for caterpillar brush 29. This floating mount has the effect of permitting the lower end of the caterpillar brush 29 to oat on the surface being swept. More specically, fthe caterpillar brush floating mount 42 comprises a pair of tracks 43 and 44 which are mounted in parallel spaced relationship on both sides of the lower housing portion 32. The tracks 43 and 44 may be provided by employing oi-set ange members which are welded or otherwise suitably secured to the sides of housing portion 32. Portions of the housing wall between Ithe complementary track members 43 and 44 are cut away as at 45 and 46 to permit free movement of caterpillar brush supporting means which extends therethrough. A caterpillar brush supporting plate 41, having small wheels or rollers 48 and 49 is disposed between each pair of complementary tracks 43 and 44, the wheels or rollers 48 and 49 being arranged to ride in tracks 43 and 44 respectively. It will thus be understood that the caterpillar brush supporting plate 41 is mounted for limited movement along a line parallel to the tracks 43 and 44.

Secured to the lower portion of the supporting plate 41 are two bearings 50 and 5I which are adapted to receive and have journaled therein sprocket axles 52 and 53. Sprocket axles 52 and 53 each carry a pair of sprocket wheels 54 (see Figure 2), over which two endless articulated -caterpillar brush chains 55 ride. At the upper end of the assembly the two endless chains 55 ride on sprocket wheels 56' which are similar to sprocket wheels 54 and which are carried on a sprocket axle 56.

Since the position of the lower end of the caterpillar brush 29 is defined by the position of the axles 52 and 53, it will readily be perceived that the position of the lower end of the caterpillar brush 29 depends upon the relative position of the brush supporting plate 41 in the complementary tracks 43 and 44.

Due to the relatively heavy weight of caterpillar brush 29, some means must be provided to partially relieve the weight of the brush and brush mechanism from the brush iibres. Such a means may be conveniently provided by counterbalancing the brush supporting plates 41. One means for providing such a counterbalance is shown in Figure l, wherein counterweights 51 are provided on opposite Asides of the vehicle I0 and are pivotally supported from the chassis I3 by means of counterweight arms 58, the counterweight arms being pivotally mounted on the support brackets 59 at an intermediate point in their length `as at 60. The counterweight arms 58 each have an overhanging portion 6| which pivotally carries the supporting link arms 62. 'I'he lower end of the link arms 62 is bolted or otherwise suitably secured to the supporting plate 41 as at 63. As is clearly shown in Figure 1 of the drawings, the lower end of each link arm 62 is preferably provided with a series of holes so that the relative length of each link arm may be adjusted at the will of the operator of the machine. A position index may be provided by employing index scale 54 on the lower housing portion 32 and a pointer 65 on the plate 41.

From the above description, it will be apparent that the greater part of the weight of the caterpillar brush 29 is released from the brush bres. Thefcounter-weights 51 are preferably adjusted on their arms 58 until the force tending to lift the caterpillar brush oi the street approaches but does not quite equal the weight which the brush bres of the brush 29 must support. In practice, it will be found that the position of the counter-weights 51 should be adjusted depending upon the type and nature of the debris which is being swept. Thus, in the Spring of the year, when there is a large amount of debris on the streets, the counter-weights 51 will be adjusted so that a greater force is bearing down on the brush fibres than in the Summer, when dust is the principal type of debris being swept up. This floating mount and counter-balancing arrangement thus provides an extremely flexible arrangement for the sweeping apparatus, since it permits ready and convenient adjustment of the apparatus depending upon the nature of the debris which is being swept. This tends to greatly prolong the average life of the brush bres.

Previous mention has been made of the fact that lower housing portion 32 is pivotally mounted for limited angular movement on upper housing portion 3|. Some means must, of course, be

provided for limiting downward movement of the housing 32, and for raising and lowering the same at the will of the operator. The means for raising housing member 32 must include means for raising caterpillar brush 29 at the same time. Accordingly, a flexible cable or chain 66 is provided for dening the lowermost position of the housing 32 which is connected at one end to the housing 32 as at 61 and at the other end to the chassis |3, as at 68.

Ad-ditional means is provided for raising and lowering the entire caterpillar brush assembly More particularly, the caterpillar brush 29 and the caterpillar brush lower housing portion 32 may be raised or lowered by means of a flexible cable or chain 69, which branches oiT- into two lower chain portions and 1| which are connected to the caterpillar brush housing 32 and the caterpillar brush supporting plate 41 respectively. The upper end of chain 69 is connected to a crank arm 12 of the control lever 13 which is pivotally mounted on the chassis I3 as at 14. Control lever 13 is preferably equipped with the usual spring biased latch (not shown) under the control of the control lever latch release 15, the latch being arranged to engage a cooperating notched latch plate 16, mounted on the side of the vehicle. As shown in Figure 1 of the drawings, when the control lever 13 is in its forward position, the caterpillar brush assembly Il is in its lowermost position, while when control lever 13 is in its rearwardmost position, the caterpillar brush 29 and the caterpillar brush housing 32 have been lifted by the chain 69 to a raised position.

' A caterpillar brush tensioning device 11 is provided to take up slack in the endless articulated chains 55 of the caterpillar brush assembly and to provide the desired amount of tension therein. As will readily be appreciated from a cursory examination of Figure 1, the degree of tension in the endless chains 55 can be governed by varying the relative spacing of the upper sprocket axle 56 from the two lower sprocket axles 52 and 53. Thus, if some means is provided for varying the distance between the upper sprocket axle 56 and the two sprocket axles 52 and 53, it is apparent that an adjustable tensioning arrangement will be provided.

More specifically, tensioning device 11 is provided by journaling the upper sprocket axle 56 in suitable bearings 18' carried on support plates 18 which are arranged to slide within complementary track members 19 and 80. These complementary track members 19 and 80 are secured to the side walls of upper housing 3| 'in parallel spaced relationship to each other, but special note should be taken of the fact that the longitudinal axis of the track members 19 and 80 are not in parallelism with the longitudinal axis of the track members 43. and 44. While the angle of divergence of the longitudinal axis of the two sets of tracks may vary within wide limits without departing from the spirit and scope of the present invention, the angle is illustrated in Figure 1 of the drawings as being approximately 20, the lower ends of thetrack members being further apart from each other than their upper ends. Due to the fact that the longitudinal axis of the track members 19 and 80 is disposed at an angle with respect to the longitudinal axis of track members 43 and 44, it will readily be appreciated that by raising and lowering the support plates 16, the tension in the endless chain 55 may be adjusted. This is by virtue of the fact that as vthe plate members 18 are lowered in their track members 19.and 80, the distance between the upper sprocket axle 56 and the two lower sprocket axles 52 and 53 is increased. 'Ihe position of the support plates 18 in the tracks 19 and is determined by clamping bolts 8| which are mounted in collars 82 to upper housing portion 3|. A position index is preferably employed by providing an index scale 83 on the sides of the housing opposite each lower track 19 and by providing a pointer 84 on the movable plates 18 of each tensioning device 11. A suitable longitudinal slot 84' is, of course, provided in the side of upper housing portion 3|.

Power for driving the caterpillar brush 29 is obtained from the motor I4, and is transferred through a'pair of drive shafts 85 (the drive shafts being illustrated in the rdrawings merely by showing the housing thereof) and then through a chain drive 86 to the upper sprocket axle 56, the necessary drive chains 81 and sprocket wheels 88 and 69 being provided for this purpose.

Power for driving the vehicle itself is obtained from the motor |4 through a second pair of drive shafts 99, one on each side of the vehicle, and a pair of drive chains 9|, the usual beveled gear boxes being provided at 92.

'I'he caterpillar brush mounting is one of the important features of this invention. Referring now to Figures 2,4, 5 and 6 of the drawings, it Will be seen that the caterpillar brush 29 is made up of a number of individual brush units 93, one complete brush unit being illustrated in Figure 5. Brush unit 93 comprises in general a brush head 94, including a channel shaped head plate 95, an intermediate grooved plate 96 and a pair of nbre supporting and clamping rods 91; and the brush proper, which is made up of a multitude of individual fibres 93 carried on the rod 91 of the brush head 94. The brush fibres 98 may be composed of any suitable material, such for example as bamboo fibres.

The channel plate 95 of each brush unit 93 is arranged to be permanently secured to the endless chain 55, such as by providing every other link 99 of the chain 55 with a fastening flange |00, which is riveted or otherwise suitably secured to the base of the channel member 95 as at The remainder of the brush unit assembly including the grooved intermediate plate 96 and the brush bre supporting and clamping rods 91 are arranged to be detachably removed as a unit from this brush head 95 which is permanently `secured to the endless chain 55. By providing fibre clamping and supporting members which may individually be removed from the caterpillar brush assembly 29, it will readily be understood that an extremely advantageous result is obtained, since it is not then necessary to remove the entire caterpillar brush assembly 29 from the vehicle I0 in order to replace or repair the brush.

The particular means illustrated in the drawings ior achieving this desired result will now be described. The intermediate grooved plate 95 of the brush head 94 is provided with two longitudinally extending grooves |02 which are substantially semi-circular in cross-sectional coniguration. A series of tubes |03 are Welded to the top of the intermediate plate member 96, and are of such length to freely slide between the side walls |64 of the channel member 95. The extent to which the intermediate plate member 96 extends into the channel of the channel member 95 is determined by the edge flanges |05 of the intermediate plate member 96 which engages the outer edges of the side walls |04 of the channel member 95. Apertures |06 are provided in the side walls |04 opposite the tubes |03 of the intermediate plate member 9B to permit bolts |01 to pass through the side walls |64 and through the tubes |03. The bolts |01 are detachably secured and held in place by nuts |08 which may be screwed onto the threaded ends |09 of the bolts |01.

The ibre supporting and clamping rods 91 are provided along their length with a plurality of threaded studs 0. These threaded studs may be butt-welded or otherwise suitably secured to rods v91. The ends of the rods 91 are bent slightly upwardly as at for a reason which will presently appear. The base of channel plate 95 is apertured as at ||2 opposite the ends of the threaded studs ||0 to accommodate variations in the length of these studs. The intermediate plate 96 is apertured also, as at ||3 for the reception of threaded studs ||0. Nuts ||4 are provided for threaded engagement with studs ||0y it being understood that these nuts ||4 tightly secure the fibre supporting and clamping rods 91 to the intermediate plate 96.

As may be seen best in Figure 6 of the drawings, the intermediate plate 96 is terminated so as to snugly t within the end Walls ||5 of the channel shaped head plate 95. It will also be observed that the end of the intermediate plate 96 is turned slightly upwardly as at ||6 in the same manner as 'the ends of the supporting and clamping rods 91 were turned up.

The brush fibres 98 are thickly grouped together and hung over each brush bre supporting and clamping rod 91, as is shown in Figure 5 of the drawings. Note should be taken that the relative spacing of the grooves |02 in the intermediate plate 96 is such that the lower ends of the brush fibres 93 overlap as at |1. It should further be noted that the grooved portions |02 of the intermediate plate 96 are shaped to intimately seat the inner or intermediate portion of the brush bres 98.

From an examination of Figure 6, it will be observed that the brush libres 98 at the extreme ends of the brush unit 93 are caused to extend slightly outwardly at an angle due to the slightly upwardly bent ends and ||6 of rods 91 and intermediate plate 96 respectively. This feature has been found to be highly desirable and extremely beneficial due to the fact that the brush fibres 98 at the outer ends of the brush unit 93 directly engage the inner surface of the caterpillar brush housing `30 (see Figure 3 of the drawings). This feature of extending the brush rlbres 98 at the extreme ends of the brush units 93 outwardly at a slight angle so as to engage the inner surface of the caterpillar brush housing 30 assures the absence of any dirt and debris leakage between the ends of the brush units 93 and the housing 39.

From the above description, it will readily be observed that the caterpillar brush unit 93 with the exception of the channel plate 95 may be readily and quickly removed and replaced. In other words, each individual brush unit 93 is separately and individually removable from the brush assembly 29. As has previously been pointed out, the caterpillar brush housing 30 is provided with a pivotally mounted lower end panel 36, which may be raised to the dotted line position shown in Figure 2 to afford ready and quick access to the caterpillar brush units 93. By raising the closure panel 36, a service man can readily reach the individual brush units 93 directly opposite, unscrew the nuts |03 and remove the intermediate plate 96 and the brush bre supporting and clamping rods 91 together with the brush fibres 93, as a unit. After a brush unit 94 has been removed from the caterpillar brush assembly 29, the brush bre clamping and supporting rods 91 may be separated from the intermediate plate 96, and the brush fibres 98 lifted out and replaced or repaired.

Access to the individual brush units 93 may also be had by removing the upper sliding cover 20.

During the sweeping operation, the caterpillar brush 29 is driven in a counterclockwise direction from the upper sprocket axle 55. The individual brush units 93 as they pass over the surface being swept cause the dirt and debris to be thrown forwardly and upwardly. In order to convey the dirt and debris upwardly to a point where it may be deposited in the hopper |2, an inclined plane ||8 (see Figure 2) must be provided immediately below the ends of the brush fibres 98. This inclined plane ||8 forms the bottom wall of the brush housing portions 3| .and 32, although it is spaced from the lower edges of the side walls of the housing portions 3|l and 32. In order to get the dirt and debris onto this inclined plane ||8, it is necessary to provide the lower end I9 thereof to diverge slightly away from the brush fibres 99 to provide a throat |20 into which the dirt and debris may be thrown by the brush. The upper portion 2| of the inclined plane I8, however, is preferably in direct contact with the lower ends of the bush fibres 98.

The dirt shoes 31, which have previously been referred to, prevent the escape of dirt and debris from the sides of the sweeping apparatus caused by the agitation of the dirt and debris by the sweeping action of the caterpillar brush 29. One type of dirt shoe which has been found extremely effective in operation and which forms one of the novel features of the present invention, is shown in detail in Figures 8 and 9 of the drawings. Each dirt shoe 31 includes a runner |22 having upturned ends 39 and 4U, which overlap the outerface of the side plate of lower housing 32. As may be seen best in Figure 8, runner |22 has substantially an L-shape cross-sectional configuration. Secured to the inner wall |23 of runner |22 is an inner plate member |24. The plate member |24 may be secured to the runner |22 in any suitable manner, such as by bolting it thereto as at |25. Inner plate member |22 is .arranged to rest against the inner wall of the housing portion 32, and to slide therealong. Thus, as the runner |22 rides along an uneven surface, the inner plate member |24 will ride up and down on the inner surface of housing portion 32, while the upturned ends 39 and 40 will ride up and down on the outer surface of housing portion 32. This overlapping engagement of the inner plate member |24 of the dirt shoe 31 prevents dirt and other debris from being thrown sidewardly from the sweeping .apparatus, irrespective of how uneven the surface is which is being swept. The curved ends 39 and 4|) of the shoe 31 and particularly the forward curved end 39 serve the dual purpose of permitting the dirt shoe to ride over any raised portions of the street, such as a rail track or a manhole cover, and also prevents the dirt shoe runner from twisting under the lower housing portion 32 and getting caught in the caterpillarbrush fibres. 'Ihe curved ends of the dirt shoe 31 thus guide the dirt shoe assembly upwardly and downwardly and also by means of the hinge arm construction cause dirt shoe 31 to rock backwardly and forwardly over undulations in the surface being swept. As has previously been pointed out, the dirt shoe 31 lis pivotally carried on the arm 38 by ,a suitable hinge connection, as at |26. The arm 38, at its opposite end, is hinged to the lower housing portion 32, as at |21. By means of this hinge arm construction and particularly by virtue of the fact that the arm 38 is pivoted at one end to the lower housing portion 32 and at the other end to the shoe runner 31, the shoe runner 31 is assured a uniform wear throughout its entire length. In other words, there is a full floating construction which provides a minimum of pressure on the street and a maximum life due to light pressure and friction.

To operate the sweeping apparatus of the present invention, power is supplied to the upper sprocket axle 56, which causes counterclockwise movement of the endless chains 55, which carry the brush units 93. Due to the fact that the lowerend of the caterpillar brush .assembly 29 is freely floating on the surface which is being swept, the lower ends of the brush fibres 98 are constantly in engagement with this surface. By properly adjusting the counterbalance weights 51, substantially all of the weight of the caterpillar `brush assembly 29 is removed from the fibres 98 themselves. The individual brushunits 93 sweep the dirt and debris forwardly and upwardlyA into the throat |29 and then upwardly along the inclined plane I8 until it arrives at the open mouth of the hopper, I2. The brush speed, of course, may vary within wide limits without departing from the spirit and scope of the present invention.

After the storage hopper I2 has become filled,

the dirt and debris collected, therein may be` In travelling to and from the area to be swept, the caterpillar brush assembly 29 and the lowerv brush housing 32 are elevated by pulling the .con-

trol lever 13 to its rearward position (that is, to its left hand position, as viewed in Figure 1 of the drawings). The position of the lower housing 32, the dirt shoes 31 and the control lever 13 when the lower housing portion 32 is in a raised position is clearly shown in Figure '7 of the drawings. When in this position, it will be noted that the exible positioning or limiting chain 66 dangles loosely as is shown in Figure '1.

In Figure 10 of the drawings, I have illustrated ,a modified form of brush unit 93 which includes a wooden brush head |28 in the place of the channel shaped head 95, previously described.

The brush head |28 is provided with longitudinally disposed recesses I 29 which are somewhatdeeper than the grooves |92 of the intermediate plate 95 of the preferred embodiment of the invention. -Brush nbre supporting and clamping rods |36 areprovided which are similar in shape to the clamping rods 91 with thev exception that the threaded studs I 3| thereon are made sufciently long to extend completely through the head 28 and through the fastening flange |32 of the link 99 of the endless chain 55. The fastening flanges |32 of the links 99 are somewhat larger than the fastening flanges |89, previously described.

The brush unit illustrated in Figure 10 of the drawings is assembled by hanging the brush bres 98 over-the fibre clamping and supporting rods |39 and then assembling the supporting rods |30 on thebrush head |28. When the nuts I 33 are screwed down on the threaded ends of the studs |3I, the brush fibres 98 are pulled tightly up into the recesses |29. It is to be understood that in this modified form of brush unit assembly, the brush head |28, the clamping rod |36, and the brush fibres 93 are all removable .'togetherfrom the fastening iiange |32 of the link 99 of the endless chain 55.

In Figures 11 and 12 of the drawings, a modified form of chain tensioning device is illustrated. The modied form of chain tensioning device shown includes a pair of arms |34 which are rigidly mounted on stud shafts (not shown) carried in bearings 35 which are bolted or otherwise suitably secured to the outer sidewalls of upper'housing member 3|. The opposite ends of the arms |34 carry a rod or axle |35 upon which two idling sprocket wheels |31 are rotatably mounted. The sprocket wheels |31 are arranged to engage the endless chainsy 55 in the manner shown in Figure 11. Mounted on the opposite .ends of the stud, shafts (not shown) upon which the arms |34 are mounted, are a second pair of arms |38. These arms |38 are rigidly secured to the stud shafts and arranged so that angular movement of the arms |38 will cause a correspending angular movement of the arms |34. Secured to the side walls of the upper housing member 3|, to the rear of and slightly below the bearings |35, are brackets |39 which carry threaded tensioning bolts |40 therein, as shown in Figures 11 and 12. Disposed between each tensioning bolt |40 and each arm |38 is a helical spring |4| under compression. The end of the tensioning bolt |30 is provided with a spring engaging ange |42, the flange |42 being located slightly back from the extremity of the bolt |40 to permit a suitable seating engagement of the compression spring |4| on the bolt |40. The end of each arm |38 is preferably provi-ded with a pin which extends slightly into the compression spring |4|, thereby to retain the same in desired position against the lower end of the arm I 38.

From a careful inspection of Figure 11, it will be observed that in this form of the invention, the longitudinal axis of the tracks 19 and 80 is substantially parallel to the longitudinal axis of the tracks 43 and 44. Since separate means is provided in this form of the invention for tensioning the endless chain 55, it will at once be obvious to those skilled in the art that it is no longer necessary to cause the longitudinal axis of the tracks 'I9 and 80 to diverge from the longitudinal axis of the tracks 43 and 44. The same type of adjustable head arrangement, however, is provided to permit a greater ilexibility of the apparatus, particularly with regard to positioning the lower surface of the brush libres with respect to the inclined plane I8. It is to be understood, however, that upper sprocket axle 56 may be directly mounted on the upper side walls of the sweeping apparatus without any arrangement being provided for adjusting the position of the axle 56 if desired. This is made possible by virtue of the fact that separate tensioning means is provided by the idling sprocket |31.

To adjust the tension in the endless chains 55 in the form of this invention illustrated in Figures 11 and l2 of the drawings, it is simply necessary to tighten up on the tensioning bolts |40. This causes the arms |38 and |34 to move in a counter-clockwise direction as viewed in Figure 11 of the drawings, thereby causing the idling sprocket wheels |31 to bear upwardly on the endless chains 55. By providing a compression spring |4| between the tensioning bolts |40 and the arms |38, a certain degree of ilexibility is provided which prevents any harm to the chains 55 such as might be caused by undue tensioning thereof. It will, of course, be understood, however, that the compression springs |4| may be omitted if desired, and the tensioning bolts |40 made of a sulcient length to directly engage the arms |38.

While I have designated my sweeper as a street sweeper, it is, of course, to be understood that I do not intend in the accompanying claims to limit the use of my sweeper solely to cleaning streets. It may be used with equal advantage in sweeping paved yards, warehouse floors, stadium floors, and numerous other similar surfaces where extensive sweeping operations are required.

While I have shown particular embodiments of my invention, it will, of course, be understood that I do not wish to be limited thereto, since many modifications may be made, and I therefore contemplate by the appended claims to cover all such modifications as may come within the true spirit and scope of my invention.

I claim as my invention:

l. In a street sweeper, a vehicle chassis, a caterpillar brush, upper and lower supporting means for mounting said caterpillar brush on said chassis, said lower supporting means being slidably mounted on said chassis to permit said caterpillar brush to float on the Surface being swept, and

at least one guide member for conning said lower supporting means to rectilinear movement.

2. In a street sweeper, a vehicle chassis, a caterpillar brush, upper and lower supporting means for mounting said caterpillar brush on said chasis, said lower supporting means being slidably mounted on said chassis to permit said caterpillar brush to float on the surface being swept, means for conning movement of said lower supporting means to a rectilinear path, and means for adjusting the spacing between said upper and lower supporting means without disturbing the path of translational movement of said lower supporting means.

3. In a street sweeper, a vehicle chassis, a caterpillar brush, a caterpillar brush housing mounted on said chassis, upper and lower caterpillar brush axles upon which said caterpillar brush is mounted, lower axle supporting plates slidably mounted on said housing and arranged to iioat said caterpillar brush on the surface being swept, said upper axle being journalled on said housing, and counterbalancing means mounted on said chassis and connected to at least one of said supporting plates for partially counterbalancing the dead weight of said brush.

4. In a street sweeper, a vehicle chassis, caterpillar brush, a caterpillar brush housing mounted on said chassis, upper and lower caterpillar brush axles upon which said caterpillar brush is mounted, upper and lower axle supporting plates upon which said axles are mounted, said upper and lower supporting plates being slidably mounted on said housing, the axis of sliding movement of said upper plate being disposed at an angle to the axis of sliding movement of said lower plate, and means for restraining sliding movement of said upper plate, said upper sliding plate providing a tensioning device for said caterpillar brush and said lower sliding plate providing a iloating mount for said caterpillar brush.

5. A caterpillar brush assembly comprising a caterpillar brush and a caterpillar brush housing including rigid substantially parallel side plates extending upwardly from the brushing zone toward a discharge point, said caterpillar brush comprising a brush head and a multitude of brush fibres secured thereto, the brush bres near the side of said brush being secured to said brush head in such a manner as to extend obliquely outwardly into continuous brushing contact with said side plates.

6. A multi-part caterpillar brush housing comprising an upper housing member including side and top walls, a lower housing member pivotally mounted on said upper housing member for movement about a substantially horizontal transverse axis, said lower housing member including side walls and a lower end wall, said side walls and said end wall of said lower housing member being disposed with respect to said side and top walls of said upper housing member that upon movement of said lower housing member about said transverse axis said lower housing member walls will telescope and overlap said upper housing member walls.

7. In a sweeping apparatus, a brush housing, sprockets in the lower rear portion of said housing', and a caterpillar brush comprising chains Vextending around said sprockets and brush units individually and separately removable from said chains, each of said brush units being attached to the chains by detachable means extending in the direction of the chains and only removable when the unit is passing over the sprocket and is angularly separated from an adjoining unit, said housing including a removable panel behind the lower rear end of said brush which provides access to said brush and permits the removal of one of said brush units from where said brush units lie in diverging angular relation on said sprockets.

8. In a sweeping apparatus comprising a 'brush and a brush housing with side walls, a pair of dirt shoes on opposite sides of said apparatus and freely mounted thereon, each of said dirt shoes including a runner and a plate member slidably nested on opposite sides of one of said side walls, said plate member extending up on one side of said side wall and said runner extending up on the other side of said side wall, said runner extending longitudinally of the apparatus and having front and rear portions overlapping said side wall.

9. A caterpillar brush and mounting therefor comprising a caterpillar brush having longitudinal chains provided with bristle brushes thereon, a supporting frame, a pair of caterpillar brush mounting means disposed at opposite ends of said brush, said mounting means being movably 10. A caterpillar brush and mounting therefor A comprising a caterpillar brush, a supporting member, a pair of caterpillar brush mounting means disposed at opposite ends of said brush and independently carried by said supporting member, one of said mounting means being freely mounted for sliding movement with respect to said supporting member, and the other of said mounting means being adjustably mounted on said supporting member for disposition in a pluv rality of selected fixed positions with respect to said member, the movement of said mounting means with respect to said supporting member being confined to downwardly diverging paths eX- tending generally transverse to the longitudinal axis of said brush.

RONALD CLEMENT EVANS. 

